External factors or influences that can impact animal health and veterinary practice
Observing animal behavior patterns
Crucial for understanding their biology, ecology, and overall well-being
Provides insights into their adaptation strategies, social structures, and reproductive strategies
Psychological processes in animals
Emotions (responses to stimuli that influence behavior)
Cognition (mental processes like perception, memory, and problem-solving)
Learning (acquiring knowledge or skills through experience, impacting future behavior)
Veterinary interference
Interventions and actions taken by veterinarians to maintain or improve the health of animals
Types of veterinary interference
Improper handling and restraint
Lack of preventive healthcare
Inadequate nutrition and feeding practices
Lack of socialization and enrichment
Delayed or inadequate veterinary care
The role of patterns and processes in veterinary interferences refers to the observation and analysis of recurring patterns and underlying processes in the field of veterinary medicine
Molecular evolution
Changes in the molecules of life (DNA, RNA, and protein) over generations, for many reasons, including mutations, genetic drift, and natural selection, resulting in different sequences of these molecules in different descendant lineages
Fundamental evolutionary processes
Mutation
Fixation
Basic varieties of mutation
Heritable mutations (occur in the germ line and are passed on in the genome of progeny)
Somatic mutations (occur in the process of cell division during normal growth and development)
Mutation
Heritable change in genetic material, including base substitutions, insertions, deletions, and rearrangements, occurring primarily during DNA replication in the production of gametes and introducing new genetic variants into the population
Fixation
The population process in which, either by genetic drift or by natural selection, a new mutation increases in frequency in a population until it replaces all other variants and reaches a frequency of 100 percent
Molecular evolution as a field of study originated when biologists discovered how to determine the sequence of proteins and started collecting data from diverse organisms in the 1970's and 1960's
Comparison of sequence divergence among proteins (fibrinopeptides, hemoglobin, and histones) revealed two important patterns: 1) Different proteins evolved at different rates, and 2) Each protein seemed to accumulate changes at a surprisingly consistent rate
Molecular clock
Refers to both a mechanism and a tool for evolutionary studies. As a mechanism, the presence of a roughly constant accumulation of change led to the inference that chance, not local adaptation is the cause of the observed molecular change. As a tool, the presence of a clock representing a molecule also meant that if its rate could be calibrated with organisms of known age (from the fossil record), then observed sequence differences for organisms without a fossil record could also be "dated"
Several observations in the mid-1960's and early 1970's challenge the dominance of selection as the driver of evolution: 1) High levels of proteins polymorphism (variation within populations) were observed in fruit flies, humans and bacteria, and 2) Extrapolating from available data, Motoo Kimura estimated that there are as many as two amino acid replacements per generation across the genome in mammals
Neutral theory
Short for neutral mutation–random drift theory of molecular evolution, proposing that molecular variation is equivalent in function (selectively neutral), making genetic drift the main driver of molecular genetic change in populations over time
Fitness
The ability of an organism to survive and reproduce in its environment, measured by an organism's genetic contribution to the next generation
Adaptation
The process by which an organism becomes better suited to its environment through genetic changes
Fitness
An organism's ability to survive and reproduce in its environment
Adaptation
Inherited characteristics that increase an organism's chance of survival
Charles Darwin's theory of natural selection is closely tied to the concepts of fitness and adaptation. Organisms with traits that improve their fitness are more likely to survive and pass on their genes, leading to an accumulation of advantageous traits in a population over time
Types of adaptation
Structural adaptation (change in physical appearance)
Physiological adaptation (biological changes on a cellular level)
Behavioral adaptation (adapted behavior based on environmental stimuli)
Fitness and adaptation are fundamental concepts in understanding how organisms, including humans, evolve and thrive in their environments
Evolution of sex
The process by which sexual reproduction and its associated mechanisms, like genetic recombination, emerged and became established in various lineages across the evolutionary tree (Phylogenetic Tree)
Phylogenetic tree
A graphical representation which shows the evolutionary history between a set of species during a period of time
Theories on the origin of sex
Repair hypothesis (sex emerged as a way to repair damaged DNA through genetic recombination)
Red Queen hypothesis (sex helps keep up with rapidly evolving parasites and pathogens)
Hill – Robertson effect (sex helps purge deleterious mutations that accumulate in asexual population)
Benefits of the evolution of sex
Genetic diversity (sex shuffles genes through recombination, creating offspring with novel combinations of traits, potentially better adapting to changing environments)
Faster adaptation (sex allows for the expression of beneficial mutations even if they initially arise in only one parent)
Reduced risk of mutations (avoiding self fertilization can decrease the risks of accumulating harmful recessive mutations)
Classification of evolution of sex by reproduction type
Sexual (mixing of genetic material from two individuals, offspring with novel combinations of traits)
Asexual (mode of reproduction that does not entail the union of sex cells or gametes)
Hermaphroditic (single organism produces both gametes, egg and sperm cell)
Dioecious (separate sexes, male and female, producing either eggs or sperm)
Types of sexual reproduction
Syngamy (fusion of haploid sex cells resulting in the formation of a diploid zygote)
Isogamy (gametes that fuse together are similar)
Heterogamy (gametes are two different sizes)
Oogamy (gametes also have different mobility)
Conjugation (two organisms come together in temporary fusion to exchange micronuclear material)
Sexual selection
An organism's ability to successfully compete for a mate or ability to choose a mate, allowing certain members of the population to reproduce more than others
Intersexual selection
Involves individuals of one sex choosing among members of the opposite sex based on the attractiveness of certain traits that those individuals possess
Intrasexual selection
Occurs in species when members of the same sex compete for access to potential mates
Purpose of sexual selection
Better survival chances for offspring
Weaker genes are eliminated not chosen to reproduce
Produce offspring
Unit of evolution
Population, as it is the smallest unit of living organism that can undergo evolution
Evolution of behavior
May involve changes in sensory system, the brain, or even anatomical changes in the structures used to carry out a behavior
Artificial selection
The process by which humans choose individual organism with certain phenotypic trait values for breeding
Natural selection
A mechanism of evolution where organisms that are more adapted to their environment are more likely to survive and pass on the genes that aided their success, causing species to change and diverge over time
Sociobiology
The study of the biological basis of social behavior among animals and humans
Phylogeny and adaptation of animal behavior provide us with evolutionary explanations that describe the history of the behavior, including which ancestor first possessed a particular trait
Concepts in the evolution of life histories
Life history patterns vary within and among species
Reproductive patterns can be classified along several continua
There are trade-offs between life history traits
Organisms face different selection pressures at different life cycle stages